This invention relates to a method and to an electro-mechanical device to be utilized on motor vehicles for the purpose of reducing fuel-waste caused by improper driving habits. Such vehicles can be, but are not limited to: passenger cars; buses; taxis; trucks; and the like.
Most motor vehicles are powered by internal combustion engines that have a multiple of power cylinders. In typical engine operation, vacuum pulses are produced in each cylinder during the intake strokes of each cylinder's piston. These individual pulses are coupled through cylinder intake-valve ports to a common manifold, where they merge and accumulate as a common vacuum termed in the trade and herein as "manifold-vacuum". This vacuum draws both combustion air and fuel through the carburetor and into the intake manifold as a mixture, to be drawn upon by each cylinder in turn during that cylinder's intake-vacuum-pulse, except in fuel injected engines where manifold-vacuum is used to draw in combustion air only.
It is well known in the automotive field that manifold-vacuum, as measured at the intake manifold, varies in direct relation to the efficiency of both engine and driving techniques, and can be interpreted as a relative indicator of vehicle gas mileage. That is, the higher the manifold-vacuum that is maintained while driving, the higher the average gas mileage that can be expected.
Manifold-vacuum, along with vehicle fuel economy, will drop in relation to the degree of loading on the vehicle and its engine produced by wind resistance, speed, degree of incline, head winds, rate of acceleration, added weight, and improper engine operating temperature.
Since drivers are unable to accurately or constantly correlate the combined effects of varying vehicle and engine loads, they tend to develop the fuel-wasting habit of driving with an unnecessarily "heavy foot on the gas pedal". A driver who could monitor manifold-vacuum while operating his vehicle could correct his driving techniques (i.e., speed, rate of acceleration, etc.) so as to maintain a higher manifold-vacuum, and obtain an improvement in gas mileage.
Existing methods of monitoring manifold-vacuum have been limited to devices that produce audible or visual signals that relate to the amount or variation of that vacuum. These devices use flashing lights, audible buzzers or beepers, or a vacuum-operated analog gauge or digital read-out to signal the driver to ease up on the gas pedal or make other adjustments in vehicle operation. The signaling parts of these devices are generally installed within close proximity of the driver.
The major disadvantage of prior methods and devices is that an excessive "reaction-loop" of sensing-and-responding is required of the driver that is not easy or automatic. The signals have to be received by the eyes or ears of the driver, interpreted by the brain, and passed on to the driver's foot. When the lights, buzzer, or beeper stops, or the vacuum reading changes, the brain must again interpret and send a conditioning signal to the foot. The driver's brain is usually preoccupied with other interpretative and decision-making acts, and would probably react to fluctuating audible or visual signals with confusion, inaction, or general annoyance. Marginal or inexperienced drivers would find such devices to be a distraction that requires undo effort and thought.
Devices that utilize buzzing or beeping sounds as a means of signaling the driver could be rendered ineffective in the presence of high noise levels in or outside the vehicle.
Devices that rely on reading a vacuum gauge or digital read-out require that the driver constantly alternate his attention from watching the road to watching the gauge or read-out to appreciate the benefits of the device. This diversion of concentration could prove to be hazardous to the average driver.
Devices that use flashing lights as a means of signaling the driver require that the lights be mounted or visually presented within the cone of vision of the driver. Changes in the direction a driver may be looking could reduce or negate the effectiveness of such signal. Also, visual signals are subject to interference from high ambient lighting, such as exists when driving in to the sun.
The existing methods and devices mentioned would present a high degree of distraction and annoyance not only to the driver, but to other passengers that may occupy the vehicle.